RU2450037C1 - Rigid polyvinyl chloride-based wood-polymer composition - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: rigid polyvinyl chloride (PVC) based wood-polymer composition contains a complex stabiliser, an impact strength modifier, wood flour and silicon sol as a binding agent, with the following ratio of components, pts.wt: polyvinyl chloride 100, impact strength modifier 4.8-9, complex heat stabiliser 4.5-7, wood flour 10-160, silicon sol 2-4.

EFFECT: obtaining highly filled rigid PVC compositions based on dispersed wood flour while preserving processing and operational characteristics.

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Description

The invention relates to the technology of rigid polyvinyl chloride compositions using silica-modified wood flour as an organic filler for the manufacture of highly filled wood-polymer materials.

A known composition based on a thermoplastic binder (polypropylene, low and high density polyethylene, polyvinyl chloride and polystyrene) and wood particles (Patent SU N1666306, CL B27N 3/02, 1991).

The disadvantages of the composition include low values of the physico-mechanical characteristics of the resulting materials while reducing the content of the polymer binder.

Known highly filled composition based on hard PVC and modified with polyorganosiloxane chalk (up to 100 parts by weight of filler per 100 parts by weight of PVC) (Markov A.V. Modification of filled rigid PVC compositions with polyorganosiloxane. - Plastic masses, 2009, No. 6, p. 36-39).

The disadvantage of the composition is that the use of filler in an amount of more than 50 parts by weight per 100 parts by weight PVC leads to a significant deterioration in the technological and operational characteristics of the material.

A known composition based on hard PVC, natural cellulose fiber and compatibilizer (US Patent No. 2008/0261019 A1. Publ. 23.10.2008).

However, the used compatibilizer is very complicated in terms of chemical composition and preparation technology, which limits its scope.

A known composition based on hard PVC, wood flour, natural polymer chitin and its derivative chitosan as binding agents (US Patent No. 7446138 B2. Publ. March 21, 2006). The dosage of the binding agent was carried out relative to the mass of wood flour and amounted to 2.5-10 wt.% Chitin and 0.5-2.5 wt.% Chitosan. The main disadvantages of the composition include the relatively low content of organic filler (not more than 120 parts by weight of filler per 100 parts by weight of PVC). It is noted that with an increase in the amount of wood flour, the strength significantly decreases and the water absorption of the resulting samples increases.

The closest in technical essence is a method of manufacturing hard PVC compositions based on wood pine flour (Yanjun Xu. Creep behavior of natural fiber reinforced polymer composites: a Dissertation for the degree of Doctor of philosophy: in School of Renewable Natural Recources / Yanjun Xu. - Loui-sia State, 2009 .-- p. 9). The maximum degree of filling with wood flour was 30 wt.% Or (40 parts by weight per 100 parts by weight of PVC). As a binding agent was used SEBS (styrene ethylene butyl styrene), which was introduced in an amount of from 0 to 5 wt.%. Samples were prepared by compression at 190 ° C.

The main disadvantages of the composition include a relatively low content of organic filler (not more than 30 wt.% Filler) and an increase in combustibility with the introduction of an organic binding agent.

The analysis of the technique and the identification of sources containing information about analogues of the claimed invention made it possible to establish that no analogues were found that are characterized by signs that are identical to all the essential features of the claimed invention. Therefore, the claimed invention meets the condition of "novelty."

The objective of the invention is to obtain highly filled (organic filler content of more than 50 wt.%) Hard PVC compositions based on particulate wood flour while maintaining technological and operational characteristics.

The result is achieved in that the wood-polymer composition based on hard PVC, containing a complex stabilizer, impact modifier, a binder and wood flour, according to the invention contains silica as a binder in the following ratio of ingredients, parts by weight:

Polyvinyl chloride one hundred Impact Modifier 4.8-9 Integrated Thermostabilizer 4,5-7 Silica sol 2-4 Wood flour 10-160

Components satisfy the following requirements:

Suspension polyvinyl chloride grade C7058M (GOST 14332-78)

Integrated stabilizer, for example Interstab (certificate No. 99-00244)

Impact modifier, e.g. FM-22

Wood flour brand 180 (GOST 16361-87)

Silica sol is a colorless or slightly colored colloidal solution of sodium silicate stabilized with sodium. The density of silica sol is 1.2 g / cm ³ , the concentration of silicon dioxide is 330-340 g / l, the concentration of sodium oxide 3.4 g / l, pH = 10.3.

For studies of PVC compositions, samples were obtained in the form of films. Silica-modified wood flour was added to the PVC composition. Film samples were prepared by thermoplastication on laboratory rollers with a 1: 1.25 friction at a roll temperature of 140-160 ° C for 5-6 minutes, depending on the composition. Rolling was carried out with a thickness of the gap between the rolls of 8-13 microns.

The properties of compositions with different degrees of filling are presented in the table.

Comparative characteristics of PVC compositions filled with initial and modified silica sol wood flour Filler (per 100 parts by weight of PVC) Indicator Strength, MPa Melt Flow Index (MFI), g / 10 min Thermostability, min No wood flour (control) 32 0.31 72 Original wood flour: 40 parts by weight 32 0.1 80 60 parts by weight or 35 wt.% (max.) 22 0 82 Silica-modified wood flour: 2 parts by weight silica sol 40 parts by weight 34 0.25 84 50 parts by weight or 30 wt.%. 34 0.25 85 60 parts by weight 34 0.22 89 80 parts by weight 33 0.15 95 120 parts by weight 29th 0 101 160 parts by weight or 60 wt.% (max.) 26 0 104 3 parts by weight silica sol 40 parts by weight 35 0.30 87 50 parts by weight or 30 wt.% 35 0.30 88 60 parts by weight 35 0.27 92 80 parts by weight 34 0.18 98 120 parts by weight thirty 0 104 160 parts by weight or 60 wt.% (max.) 27 0 108 4 parts by weight silica sol 40 parts by weight 36 0.27 91 50 parts by weight or 30 wt.% 36 0.27 93 60 parts by weight 36 0.25 97 80 parts by weight 35 0.16 103 120 parts by weight 31 0 109 160 parts by weight or 60 wt.% (max.) 28 0 113 Prototype: there is no data there is no data 30 wt.% + 0% SEBS 27 30 wt.% + 2.5% SEBS 29th 30 wt.% + 5% SEBS 25

The degree of filling of the proposed hard PVC compositions in comparison with the prototype was able to increase by 2 times (from 30 to 60 wt.% Wood flour).

Strength indicators are maintained even at high degrees of filling (up to 60 wt.% Per 100 parts by weight of PVC) and combustibility decreases when an inorganic binder is added to the composition of PVC compositions.

An increase in melt flow rate by 50 parts by weight wood flour is apparently associated with the achievement of the optimal concentration of silica sol and lignin, which acts as a plasticizer. A further increase in viscosity is natural with an increase in the amount of filler.

Claims (1)

A wood-polymer composition based on hard polyvinyl chloride - PVC, containing a complex stabilizer, impact modifier and wood flour, characterized in that it contains silica as a binding agent, parts by weight:
Polyvinyl chloride one hundred Impact Modifier 4.8-9 Integrated Thermostabilizer 4,5-7 Silica sol 2-4 Wood flour 10-160